Tailoring bismuth telluride nanostructures using a scalable sintering process and their thermoelectric properties
Tailoring bismuth telluride nanostructures using a scalable sintering process and their thermoelectric properties
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DOI：
10.1039/c4ce00837e
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发表时间：
2014-01-01
期刊：
影响因子：
3.1
通讯作者：
Hayakawa, Y.
中科院分区：
文献类型：
--
作者：
Anandan, P.;Omprakash, M.;Hayakawa, Y.
采用湿化学法合成了碲化铋(Bi2Te3)纳米晶，采用高压高温烧结(HPHTS)工艺制备了直径为10 mm、厚度为1 mm的纳米晶颗粒。采用烧结法制备了纳米结构，并利用标准分析技术研究了烧结温度对球团状Bi2Te3纳米晶形态演变和相变的影响。在高温下烧结的球团中观察到了从Bi2Te3到BIT的相变，773K下烧结的球团中以咬合相为主。测试了制备的和烧结的球团的热电性能。Bi2Te3纳米晶的Seebeck系数随着烧结温度的升高而增大，在较高的烧结温度(673K)下，Seebeck系数减小。此外，烧结显著提高了Bi2Te3纳米晶的功率因数。用Bi2Te3烧结体的相和形貌变化模型解释了Seebeck系数和功率因数的变化。
Bismuth telluride (Bi2Te3) nanocrystals were synthesized using a wet chemical method, and 1 mm thick pellets of nanocrystals with a 10 mm diameter were made using a high pressure and high temperature sintering (HPHTS) process. The nanostructures were tailored using the sintering process, and the impact of the sintering temperature on the morphological evolution and phase transformation of the pelletized Bi2Te3 nanocrystals were studied using standard analytical techniques. A phase change from Bi2Te3 to BiTe was observed in pellets sintered at high temperatures, and the BiTe phase dominated in the pellets sintered at 773 K. The thermoelectric properties of the as-prepared and sintered pellets were measured. The Seebeck coefficient of the Bi2Te3 nanocrystals increased with sintering temperature, and decreased at higher sintering temperatures (>673 K). Moreover, the power factor of the Bi2Te3 nanocrystals was significantly enhanced by sintering. The variations in the Seebeck coefficient and power factor are explained with a proposed model using the phase and morphological changes in the sintered Bi2Te3 pellets.